Process fob recovering hydrocar-



@as Sie@ May 17, 1938. M P YOUKER Re. 20,730

l PROCESS FOR R'ECOVRI'NG HYDROGARBON LIQUIDS FROM VOLATILE HYDROCARBONGASES AND .VAPORS Original Filed May 15, 1931 Condensep Vapor HiluxCarmona-or IN VEN TOR.

- 4Resauerl May 17,- 1938l sus I PEOSS FOR BECOVBING HYDBOCAB.- BONLIQUIDE` FROM VOLATIIYE-HYDB0- CARBON GASES AND VAPGBS Malcolm P. You,Bartlesville, mim

to Phillips Petroleum Company, Okla.,.a oorporationof DelawareBartlesville,

Original `N0.'1,`951,383, lated Mll'oll 20,' 1934, 8e-

l'ial No'. 537,152, May 13, 1931.'A Application for relsllle Milch 21,1936, Serial No.v 70,177

s clums.- A (ci.v 19o- 11) d.

My invention relates to the recovery of hydrocarbon liquids from.volatile hydrocarbon vapors and gases and has specialreference to therecovery of casinghead gasoline from natural gas by 5 a process whichwas disclosed lln` an application for patent filed by Malcolm P. Youkerin the United States `Patent Oillce April 8, I1926 under UnitedStatesPatent Oiilce Serial Number 100,- 583 for a Process for recoveringhydrocarbon liquids from volatile hydrocarbon gasesfnd vapors. `Thisapplication for patent should be taken as a continuation in part of saidprevious patent application. An object oi my invention is.

to provide an emcient method by which hydroi' carbon liquids may berecovered from vvolatile hydrocarbon vapors and gases. By my inventionthis advantage is accomplished and likewise other advantages which willbe apparent. I

My invention will be more fully understood- 2u from thefollowingdescription-taken in connection with the accompanying drawing, in whichone form of apparatus by `which my 'new process maybe carried outilsdiagrammatically illus- `trated in side elevation:

Referring to the drawing, the numerals I, 2

and 3 designate closed vertical cylindrical vessels, 4 is a bubblingtype fractionating column in whichv are disposed bubbling plates. I. vBubbling. plates 5 are equipped with bubble'V caps 5 and overtlowltubes 1. A condenser box I is filled with cold water. The numbers 8, Il.II, I2, I2, I4. I5, I6, I1, Il, and I9-l`ndic`ate pipe lines which arerepresented by lines. Pipe I is in communication with a supply'of gaswhich is to be processed `and leads into the lower portion oi'gvessel I.Pipe III, in which is mounted .a pump 24, leads from the lower portionof vessel 2 into the upper portion of vessel If The pump 24 operates topump from vessel 2 into vessel I. Pipe II, in

which is mounted a valve2| leads from the center of vessels! into thecenter of vessel-2. Pipe` I2, in which is mounted a gas compressor 25,leads from the top of vessel 2 into the fractionating column 4 betweensome of bubble plates i. The compressor 2l operates to pump 'vapori'rom.

vessel 2 into fractionating column 4. Pipe il leads from the top of thefractionating column 4 through condenser 8 and into the central portion'of vessel I. Pipe I4 leads from the bottom su ofvessel I into the topoifractionating column 4.

Pipe Il which is in communication with a supply of steam leads throughac'oii in the bottom of the fractionating column and thence totheatmosphere. Pipes Il and Il le`ad'from the bottoms of iractionating`column] andvessel 2 reaccumulate in the bottom of vessel 2 will by meansin vessel'I.

spectively. Valves 22 and 2l are mounted in pipes I1 and I6Arespectively. A pipe Il leads from the top of vessel I. Pipe I9, inwhich is mounted an adJustable loaded valve 2l, leads from the top ofvessel I. I'he vloaded valve 2li operates to hold pressure in vessel- I.-l

'I'his apparatus will be operated to carry out my new' process in thefollowing manner:-

'l'he vessel I will be maintained partially filled with hydrocarbonliquid which haslpreviously been recovered by the process. Raw gas whichcontains desirable hydrocarbon liquids will be passed into the vessel Ithrough the pipe I lancl will bubblethroush the liquid which is held inthe vessel I. A pressure equal to orpreferably above atmosphericpressurefwill be maintained As a result oi the contact between liquidand raw gas in the vessel I, liquid contained in the raw gas will beliquefied in the vessel I. Residual denuded dry gas will pass from thevessel I through the pipe I8.l Through manipulation oi' the valve 2|'liquid which will accumulate in vessel I will constantly bedischarged Ythrough pipe I I into vessel 2 and liquid which will of pump 24 beconstantly discharged through B5 pipe Il into the upper portion ofvessel I. The compressor 2B will be operated to maintain a pressurepreferably below eight pounds per square inch absolute in thevessel 2.The loaded valve III will be setto hold a back. pressure preferablyabove one hundred pounds per square inch gauge pressure, Some of themore' volatile constituents of the liquid which will flow from vessel Ithroughpipe II into) vessel 2 willias a result M Jthe low pressuremaintained in vessel 2 be vaporized in vessel' 2 and the vapoi` thusproduced will be^torced by the'compressor 2l to flow through pipe I2into .the fractionating column L 4 and thence'upward through the'fractionating column 4 and through the pipe Il. Some of theleastlvolatile constituents ofthe vapor passing through the'pipe Il willbeI condensed while passing through the condenser l and the resultantmixture of gas and liquid will ow into the veslsel I. where a separationoi' liquid and 'gas will rising through the fractionatin'g column.Liquid will accumulate in thej'fractionating column and will 'be heatedbyz means of passing steam through the pipe It.d Through une operations:

valves l23 and 22 liquid products of the process will be withdrawn fromthe bottom of the rectifying column and the bottom of the .vessel 2through pipes Il and i1 respectively. The liquid drawn from therectifying column will be cooled on the way to storage. l.

The volatility of the liquid drawn from the rectifying column maybedecreased by decreasing the back' pressure held by loaded valve 2l orby increasing the quantity of steam supplied through pipe I l and viceversa. The volatility o! the liquid drawn from the vessel 2v throughpipe i1 may be decreased bydecre'asing the pressuremaintained in thevessel 2 v and vice versa.

It should be understood that. while I recommend that a pressure of'l 100pounds per square inch, or more, be maintained in thel fractionatingcolumn 4 andthat an absolute pressure oi' about 8 pounds per square'inchbe maintained in the separator 2, the process may be operatedsuccessfully when other pressures are maintained in these parts of theapparatus. It will be found advantageous to vary both the pressuremain-v .tained in separator l2 and the pressure main- .tained iniractionating'column 4 in accordance with variations in the vaporpressure of the 'gasolinewhich is to be recovered by the process; j

I have found that when operating a high pressure .stabilizingfractionating column such as thel fractionating column 4, thetemperature of cooling .water-available for condensing purposes be ingfrom 60 F. to 90 F., it is advantageous to vary the pressure under whichsuch a fraction. ating. column is operated Vfrom about 60 pounds persquare inch gauge when making gasoline having a vapor pressure of 10pounds per square inch absolute'to about 200 pounds per square inchgauge when making a gasoline having a vvapor pressure of about poundsper square inch absolute. The desirable pressure which should bemaintained in the fractionatingcol# umn 4 would vary with the vaporpressure specication for the gasoline to be produced and withv thetemperature of cooling water availabler for condensing purposes. I wouldrecommend that the fractionating column 4 be so constructed as to be.capable oi' standing250 pounds per square inch pressure andv that aback pressure-valve 2l be provided which is adjustable to/h'old any backpressure between 50 pounds per square inchfand 250 pounds per squareinch. With such equipment and a normal supply of condensing water.gasolines having a vapor pressure vvarying between 10 pounds per squareinchabsolutejand 35 s rpounds per square inch absolute could readily. beproduced at vthe bottom of the -fractionuting column 4. The. vaporpressure sp'ecldcation' for natural gasolines which are commonly in usevary from a minimum ofy about 12 pounds vper square in'ch absolute toabout 35 pounds absolute. It'is of course desirable to operate fractionating column 4 under 'theA lowest possible pres- -sure compatible withthe manufacture of a given grade of gasoline in order that the powerinput required for the operation of the compressor 2l may be held at aminimum.

Irwin also bemand advantageous to vary the pressure maintained in theseparator 2 with the of gasoine manufactured. The maintenance of amaximum premure in separator .2 will of course result in al minimum`power' .input requirement 4for the operation vof compressor 2l and inorder to save power it`jis then desirable to maintain a maximumpressureinliquid retained inv separator :2. is inreased, therateofcirculation of such liquid through the absorber l with respect tothe gas passing through absorber i must be increased, whichref suits inincreasing the power input required by the pump 24. The exact pressurewhich maintained in separator- 2 will result in a minimum combined powerrequirement by. the pump 24 and the compressor 25 is diflicult todetermine and can only be approached by a careful study .in anyparticular case. The liquid retained in 'separator 2 will serve as anabsorbent for gasoline which is contained in the raw gas so. long as theabsolute pressure maintained in separator 2 is below the absolutepressure maintained'at the 'separator 2. Howevenasthevapor of the lpoint where gasoline is absorbed. The pressure maintained in separator 2`should for economic operation be at least 8 pounds below the vaporpressure o't the gasolinewhich isto be manufactured by the process whentaken at the tempera- .tureoi the raw gas'passing through the absorberI; I would recommend thatthe separator 2 and the compressor 2l be so.constructed that .an abso-l lute pressure as low as 2 pounds per'squareinch maybe maintained in the separator 2, then by varying the speed ofthe compressor 25 the pressure maintained in separator 2V may be variedfrom 2 pounds absolute when recovering gasoline which has a vaporpressure of l0 pounds absolute to 15 pounds or 20 pounds abslolute whenrecoverlng gasoline which has a vapor pressure of pounds absolute.

From the above it will be clear that thepressure maintained in theseparator 2 may be varied Vfrom about 2 pounds per square inch absoluteto aboutil pounds per.y square inch absolute, depending on thenature ofthe gasoline to be recovered. It will also 'be clear4 from the' abovethat. the pressure maintained in the fractionating column 4 should bevaried from about 50 pounds per square inch gaugepressure toabout 250pounds per square.V inch gauge pressure,fde.

pending upon the character of the gasoline to be recovered. I Itis to`be noted that desirable constituents of the raw gas are liqueiied bymeansof altering rthe composition of the rawgas andthat this alterationof composition is accomplished by adding to the raw gas some of. thepreviously r'ecovered least volatile constituents of likc'raw gas. Itshould also be noted vthat by my new process a large part of the workwhich necessarily attends the recovery of casinghead gasoline fromnatural gas-through theluse of the conventional. gasoline contaminating,extraneously supplied and comparatively non-volatile absorption oil iseliminated. l

Although I have vshown one method oi'` carrying out my new processit'should be understood'that I do not wish to limit myself to the methodshown -but intend to claim broadly all the new end novel features whichare inherent in my new process. For instance, while I. have shownhow-the gasoline absorbed from the gasmay be divided into a vaporousfraction and a liquid fraction/ by means of introducing said absorbedgasoline into a region wherejthe pressure is electv to separate .saidabsorbed .gasoline into /said liquid and vaporous fractions by heatingsaid absorbed gasoline andsubeeguelllycool that part' o! said liquidfraction. it

f for an absorbent for more 4 "f I claim:

1. A process for recovering hydrocarbon liquids from lhydrocarbon'gaseswhich consists in caus- `ing a hydrocarbon gas 'to make contact withgasoline in a zone maintained at a relatively high pressure,subsequently releasing the liquid which results from said contact intoa' zone of relatively low pressure to separate said liquid into 4avaporous fraction and a liquid fraction, returning at least a portionofv said liquid fraction to said ilrst zone -ior utilization as anabsorbent medium in the-process, and rectifying said vaporous fractionunder superatmospheric pressure to produce therefrom a liquid and agaseous fraction.

2. A processior recovering hydrocarbon" liquids from hydrocarbon gaseswhich consists in Acausing a hydrocarbon gas to make contact withgasolinel in a zone maintained at a relatively high pressure,subsequently releasing the liquid which results from said contact into azone maintained under absolute pressure below twenty pounds per squareinch to separate said liquid into a vaporous fraction and a liquidfraction, returning at least a portion of said liquid fraction to saidrst zone for utilization as an absorbent medium in the process, andrectii'ying said vaporous fraction under super-atmospheric pressure toproduce therefrom a liquid and a gaseous fraction. f f

3. A process for recovering hydrocarbon liquids from hydrocarbon gaseswhich consists in causing a hydrocarbon gas to make contact withgasoline in a zone maintained at a relatively high pressure,lsubsequently releasing the liquid therefrom a liquid undersuper-atmospheric press-ure to produce therefrom aliquidand a gaseousfraction. 1' 4. A process for recovering hydrocarbon liquids fromhydrocarbon gases which consists in causrectifying said vaporousfraction to produce therefrom a liquid and a gaseous iraction,condensing a portion of .said gaseous fraction and reiiuxing saidcondensate to the rectication zone.

5. A process for separating from hydrocarbon gas some of the leastvolatile constituents or' said Agas which consists in contacting saidgas [while under comparatively high Lpressure with an absorption mediumcomprising gasoline recovered in the process, subsequently releasing theliquid which results from said contact into .a region of comparativelylow pressure and com-- pressing and rectifyingY the gases which result`from said releasingof pressure on said mixture. t

6. A process for recovering hydrocarbon4 liquids lfrom hydrocarbonygases including the steps of *causing a hydrocarbon gas to make contactwith a. hydrocarbon absorption liquid which boils within the gasolinerange,lin a zone maintained at relatively high pressure, subsequentlyreleasing the liquid which results from said contact into a zone 'ofrelatively low pres sure to separate said iiquidinto a vaporous fractionand a -liquid vfraction, returning at least a portion of said liquidfraction to said iirst zone, for utilization as an absorbent medium inthe process, and rectifying said vaporous fraction under.superatmospheric pressure to produce and gaseous fraction. y i MALQOIMP. YOUKER.

